Adding support for pysnmp version6 (#3473)

Co-authored-by: Tonygratta <[email protected]>

netmiko/snmp_autodetect.py

@@ -23,11 +23,18 @@
 
 from typing import Optional, Dict, List
 from typing.re import Pattern
+import asyncio
 import re
 import socket
 
 try:
     from pysnmp.entity.rfc3413.oneliner import cmdgen
+
+    SNMP_MODE = "legacy"
+except ImportError:
+    from pysnmp.hlapi.asyncio import cmdgen
+
+    SNMP_MODE = "v6_async"
 except ImportError:
     raise ImportError("pysnmp not installed; please install it: 'pip install pysnmp'")
 
@@ -304,12 +311,14 @@ def __init__(
                 self.snmp_target, timeout=1.5, retries=2
             )
 
-    def _get_snmpv3(self, oid: str) -> str:
+    async def _run_query(self, creds: object, oid: str) -> str:
         """
-        Try to send an SNMP GET operation using SNMPv3 for the specified OID.
+        Asynchronous getCmd query to the device.
 
         Parameters
         ----------
+        creds : UsmUserData or CommunityData object
+            The authentication credentials.
         oid : str
             The SNMP OID that you want to get.
 
@@ -318,26 +327,82 @@ def _get_snmpv3(self, oid: str) -> str:
         string : str
             The string as part of the value from the OID you are trying to retrieve.
         """
-        cmd_gen = cmdgen.CommandGenerator()
-
-        (error_detected, error_status, error_index, snmp_data) = cmd_gen.getCmd(
-            cmdgen.UsmUserData(
-                self.user,
-                self.auth_key,
-                self.encrypt_key,
-                authProtocol=self.auth_proto,
-                privProtocol=self.encryp_proto,
-            ),
+        errorIndication, errorStatus, errorIndex, varBinds = await cmdgen.getCmd(
+            cmdgen.SnmpEngine(),
+            creds,
             self.udp_transport_target,
-            oid,
-            lookupNames=True,
-            lookupValues=True,
+            cmdgen.ContextData(),
+            cmdgen.ObjectType(cmdgen.ObjectIdentity(oid)),
         )
 
-        if not error_detected and snmp_data[0][1]:
-            return str(snmp_data[0][1])
+        if not errorIndication and varBinds[0][1]:
+            return str(varBinds[0][1])
         return ""
 
+    def _get_snmpv3_asyncwr(self, oid: str) -> str:
+        """
+        This is an asynchronous wrapper to call code in newer versions of the pysnmp library
+        (V6 and later).
+        """
+        return asyncio.run(
+            self._run_query(
+                cmdgen.UsmUserData(
+                    self.user,
+                    self.auth_key,
+                    self.encrypt_key,
+                    authProtocol=self.auth_proto,
+                    privProtocol=self.encryp_proto,
+                ),
+                oid,
+            )
+        )
+
+    def _get_snmpv3(self, oid: str) -> str:
+        """
+        Try to send an SNMP GET operation using SNMPv3 for the specified OID.
+
+        Parameters
+        ----------
+        oid : str
+            The SNMP OID that you want to get.
+
+        Returns
+        -------
+        string : str
+            The string as part of the value from the OID you are trying to retrieve.
+        """
+        if SNMP_MODE == "legacy":
+            cmd_gen = cmdgen.CommandGenerator()
+
+            (error_detected, error_status, error_index, snmp_data) = cmd_gen.getCmd(
+                cmdgen.UsmUserData(
+                    self.user,
+                    self.auth_key,
+                    self.encrypt_key,
+                    authProtocol=self.auth_proto,
+                    privProtocol=self.encryp_proto,
+                ),
+                self.udp_transport_target,
+                oid,
+                lookupNames=True,
+                lookupValues=True,
+            )
+
+            if not error_detected and snmp_data[0][1]:
+                return str(snmp_data[0][1])
+            return ""
+        elif SNMP_MODE == "v6_async":
+            return self._get_snmpv3_asyncwr(oid=oid)
+        else:
+            raise ValueError("SNMP mode must be set to 'legacy' or 'v6_async'")
+
+    def _get_snmpv2c_asyncwr(self, oid: str) -> str:
+        """
+        This is an asynchronous wrapper to call code in newer versions of the pysnmp library
+        (V6 and later).
+        """
+        return asyncio.run(self._run_query(cmdgen.CommunityData(self.community), oid))
+
     def _get_snmpv2c(self, oid: str) -> str:
         """
         Try to send an SNMP GET operation using SNMPv2 for the specified OID.
@@ -352,19 +417,23 @@ def _get_snmpv2c(self, oid: str) -> str:
         string : str
             The string as part of the value from the OID you are trying to retrieve.
         """
-        cmd_gen = cmdgen.CommandGenerator()
-
-        (error_detected, error_status, error_index, snmp_data) = cmd_gen.getCmd(
-            cmdgen.CommunityData(self.community),
-            self.udp_transport_target,
-            oid,
-            lookupNames=True,
-            lookupValues=True,
-        )
+        if SNMP_MODE == "legacy":
+            cmd_gen = cmdgen.CommandGenerator()
+            (error_detected, error_status, error_index, snmp_data) = cmd_gen.getCmd(
+                cmdgen.CommunityData(self.community),
+                self.udp_transport_target,
+                oid,
+                lookupNames=True,
+                lookupValues=True,
+            )
+            if not error_detected and snmp_data[0][1]:
+                return str(snmp_data[0][1])
+            return ""
 
-        if not error_detected and snmp_data[0][1]:
-            return str(snmp_data[0][1])
-        return ""
+        elif SNMP_MODE == "v6_async":
+            return self._get_snmpv2c_asyncwr(oid=oid)
+        else:
+            raise ValueError("SNMP mode must be set to 'legacy' or 'v6_async'")
 
     def _get_snmp(self, oid: str) -> str:
         """Wrapper for generic SNMP call."""